More than half of the users reuse password access to many different online services, according to Virginia Tech 2018. This means it can be very bad news if the data leak on the Internet from hacking or data breaches, as hackers can then use this data to access other accounts.
You often have to change your password for that site after a violation, but you are still in danger if this password is used elsewhere.
If you are worried, the website HaveIBeenPwned allows you to see if your email address is between stolen data and has leaked electronically to data breaches.
If you find that your email data has leaked, make sure that the password will not be used again (because it can be used to access social accounts and purchase accounts by resetting your password).
You can also use HaveIBeenPwned to see how many times your password has leaked into data breaches (if it is common, it is more exposed to violent hacker attacks, where automated machines "guess" any possible password).
Here are some of the biggest violations of the last two years.
Facebook recognized many incidents where data remained exposed last year, either through Facebook or through app developers who had access to Facebook data.
In an attack, hackers gained access to data from 29 million accounts, including information such as location and relationship status.
Data from Facebook accounts, including passwords, remained unsafe and exposed, including 540 million files with items like Likes, account names and comments, researchers found earlier this year.
This week, WhatsApp warned that a vulnerability in its service could leave 1.5 billions of users exposed to a hacker. Attackers could place malicious code on a user's device simply by making a call, admitted the company. Since then, vulnerability has been corrected, but users have to update their application to be safe.
Microsoft e-mail services (Hotmail, MSN, Outlook)
Microsoft admitted in April of 2019 that hackers gained access to data from MSN, Hotmail and Outlook accounts through the Microsoft Customer Support Portal. Microsoft said a "limited" number of users had been affected, but recommended that users change their passwords.
The hacker had access to T-Mobile's servers and stole data, including personal data and passwords for two million users.
Data, including credit card details, leaked from British Airways' electronic services at the end of 2018, with up to 500.000 customers affected. British Airways warned customers who bought or modified their bookings in August and September of 2018 that their data may have been stolen.
The online Quora service admitted that a malicious person had accessed 100 million user accounts in November of 2018.
The Google Plus social network was abolished abruptly after a huge data breach in October of 2018, which affected 52,5 personal data for millions of people. The flaw could have allowed apps to collect information, including e-mail addresses, professions, gender, and age.
The popular Houzz interior design application saw 49 million user data leak into a large-scale data breach that occurred in 2018's media.
Users were informed that the data, including email addresses, locations and encrypted passwords, had leaked in February of 2019.
The popular photo service admitted in February of 2019 that 14,8 million user data had leaked with full names, email addresses, birthdates and locations.
The popular fitness and nutrition service suffered a 2018 data breach, from which 144 leaked millions of email addresses along with user names, addresses IP and encrypted passwords.
The email verification service admitted that customer data had remained on the Internet without a password-free guarantee. Up to 763 millions of e-mail addresses have remained exposed.